State Key Laboratory of Biocontrol, School of Life Sciences , Sun Yat-sen University , Guangzhou 510275 , China.
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry , Chinese Academy of Science , Guangzhou 510640 , China.
Environ Sci Technol. 2018 Mar 20;52(6):3634-3641. doi: 10.1021/acs.est.7b05854. Epub 2018 Mar 1.
Phototransformation is one of the most important transformation pathways of organic contaminants in the water environment. However, how active compounds enable and accelerate the phototransformation of organic pollutants remains to be elucidated. In this study, the phototransformation of benzo[a]pyrene (BaP, the first class "human carcinogens") by various natural porphyrins under solar irradiation was investigated, including chlorophyll a, sodium copper chlorophyllin, hematin, cobalamin, and pheophorbide a. Transformation efficiency of BaP varied considerably with chemical stabilities of the porphyrins. Porphyrins with a lower stability displayed higher BaP transformation efficiencies. BaP transformation had a significant positive correlation with the production of singlet oxygen. Identical phototransformation products of BaP were observed for all investigated porphyrins, and the main products were identified as BaP-quinones, including BaP-1,6-dione, BaP-3,6-dione, and BaP-6,12-dione. The mechanism of natural porphyrins accelerating the BaP phototransformation in water was proposed to proceed via the photocatalytic generation of singlet oxygen resulting in the transformation of BaP to quinones.
光转化是水环境中有机污染物最重要的转化途径之一。然而，活性化合物如何促进和加速有机污染物的光转化仍有待阐明。在这项研究中，研究了各种天然卟啉（叶绿素 a、铜叶绿素钠、血晶素、钴胺素和原卟啉 a）在太阳照射下对苯并[a]芘（BaP，第一类“人类致癌物”）的光转化，包括叶绿素 a、铜叶绿素钠、血晶素、钴胺素和原卟啉 a。BaP 的转化效率随卟啉的化学稳定性而有很大差异。稳定性较低的卟啉显示出更高的 BaP 转化效率。BaP 的转化与单线态氧的产生呈显著正相关。所有研究的卟啉都观察到 BaP 的相同光转化产物，主要产物被鉴定为 BaP-醌，包括 BaP-1,6-二酮、BaP-3,6-二酮和 BaP-6,12-二酮。提出了天然卟啉在水中加速 BaP 光转化的机制，该机制通过光催化生成单线态氧导致 BaP 转化为醌。
